The proposed program represents continuation of a multidisciplinary series of fundamental investigations into the interrelationships between the central nervous system, monoamine neurons and arterial hypertension. The broad objectives of these studies are to (a) identify and characterize the physiological effects upon the systemic and cerebral circulation of brain regions, including the nucleus tractus solitarii (NTS), fastigial nucleus and dorsal medullary tegmentum, important in regulating the systemic arterial pressure (BP); (b) examine the role of the CNS in controlling the release of catecholamines from the adrenal medulla; (c) examine the role of glutamate as the neurotransmitter of baroreceptors in the NTS; (d) characterize the behaviorally associated changes in BP in rat with spontaneous hypertension and brain lesions; (e) analyze the neurochemistry of central catecholaminergic systems, particularly with respect to their biosynthetic enzymes; (f) investigate the neuroanatomy of peptidergic pathways in brain by immunocytochemistry, particularly with respect to their development and interaction with catecholamine systems; (g) study the cellular mechanisms governing differentiation, growth and regeneration of adrenal medulla.